Written by Radmehr Abdollahi
Currently, behavioral therapies such as laughter therapy (LT) are not the primary intervention for improving mental health. Laughter in the mammalian brain engages the limbic system and several reward pathways that regulates mood. Several RCTs and open-labeled trials on LT have seen improved levels of depression, anxiety, stress and fatigue. However, many studies are of low quality or have certain biases in their design which makes it difficult to conclusively identify the degree to which LT improves mental health. Despite the lack of robust studies, LT remains a safe and convenient treatment unlike psychiatric medications. With more concrete evidence via RCTs, LT can potentially be an alternative and/or complementary treatment for mental health.
Laughter is a phenomenon observed in many species, most notably in humans1. Ever since the concept of evidence based medicine (EBM) entered the scientific community, debates have arisen around the effectiveness and practicality of behavioral interventions such as LT to prevent or treat disease. Anecdotal strengths of laughter as therapy include benefits to mental health, encapsulating the alleviation of a variety of conditions, the most common of which being depression, anxiety, and stress. This piece aims to examine the physiology, effectiveness and feasibility of LT on the mental health of individuals who are seeking alternative solutions to calm their minds and eliminate mental suffering.
It has been shown that mirthful, or active laughter has substantial effects on the circuitry of the human stress response system. Although comprehensive research on the value of laughter is limited, several recent trials have found therapeutic benefits. Such benefits include decreases in stress hormone levels (e.g. epinephrine and cortisol) and increases in the activation of the mesolimbic dopaminergic reward system2. This reward pathway in the mammalian brain is the major reward pathway that connects the ventral tegmental area (VTA) in the midbrain to the ventral striatum of the basal ganglia in the forebrain3. Through this pathway, dopamine is sent via the VTA to vital regions such as the nucleus accumbens, amygdala, and hippocampus — all of which have complex and evolutionary functions in laughter stimulation, emotional regulation and memory4. Besides the importance of dopamine and serotonin in mental health, endorphins, the famous endogenous opioid peptides, can also be produced by mirthful laughter. Endorphins not only are capable of acting as natural anesthetics for low pain levels, but they are also important neurotransmitters that help mediate human happiness5. While the majority of these benefits in the human body have been obtained by anecdotal evidence, theories or small scale trials, the therapeutic value and mechanism of laughter theory in a practical setting is still an area for further investigation.
Despite the many anectodal benefits of LT, research is still in its early stages to conclusively deduce the therapeutic value of this alternative behavioral therapy. However, several randomized controlled trials have helped produce systematic reviews that holistically examined the effectiveness of laughter yoga interventions for different conditions such as cancer-related side effects including depression, fatigue and hopelessness. Due to the ease of application and accessibility of this intervention, its efficacy has primarily been studied in cancer patients and the elderly. One comprehensive systematic review conducted in 2019, created a meta-analysis on laughter-inducing therapies and concluded that, despite varying study quality and risk of biases of many of the included trials, both simulated (non-humorous) laughter and spontaneous (humorous) laughter have positive effects on depression and anxiety6. The review also noted that positive trends were found in the analysed studies that showed lower cortisol and pain levels in the participants. However, the open-labeled nature of the trials made it difficult to exclude confounding factors and, thus, the results remain inconclusive.
Other studies have also been conducted to add on to the aforementioned review, including the 2011 Korean RCT by Cho et al., which investigated the effects of laughter on the following outcomes in breast cancer survivors: depression, quality of life (QOL), resilience, and immune responses, all of which work hand in hand to determine mental health status7. The study reported that although improvements were seen in the self-reported QOL and resilience levels, depression and immune responses did not differ significantly. Therefore, despite the majority of trials that have shown the benefits of LT, some studies have received varying results, encouraging further research to take place to make this hypothesis more conclusive.
Accessibility and cost:
Despite debate around the therapeutic value of this intervention, its proponents believe that LT is not only a harmless intervention compared to psychiatric medications, but can also be vastly made available to immobile and imparied individuals, such as chronically ill patients and/or the elderly, for little to no cost. With rising health care costs and the prospect of an increasing elderly population, simple interventions such as LT can be combined with music, exercise and socialization for positive mental health benefits. Standard LT programs can also be designed for health care workers and nurses with minimal training6. Although this intervention might be unable to replace current pharmacological interventions for medium-severe mental health issues, it can be an excellent alternative method that can aid the many individuals struggling with mild depression and anxiety.
Despite a number of comprehensive systematic reviews, meta-analyses and RCTs, the limitations and potential areas of bias of LT trials make it difficult to assess the extent to which laughter is effective in improving mental health. Blinding of the intervention and study objective is not possible due to the nature of this intervention. This may bias study results, as participants may be influenced to report outcomes that create a positive association between the intervention and outcome. Considering the methodological challenges in assessing behavioural therapies such as this, it can be concluded that both stimulated (by tickles) and spontaneous (by humor) laughter are effective in improving mental health to varying degrees. More methodologically rigorous research is needed in this area for LT to become a mainstream prescription for physicians.
1. Yim JE. Therapeutic Benefits of Laughter in Mental Health: A Theoretical Review. The Tohoku Journal of Experimental Medicine. Tohoku University Medical Press; 2016 . Available from: https://www.jstage.jst.go.jp/article/tjem/239/3/239_243/_html
2. Savage BM, Physiology Dof, Lujan HL, Thipparthi RR, DiCarlo SE. Humor, laughter, learning, and health! A brief review. Advances in Physiology Education. 2017. Available from: https://journals.physiology.org/doi/full/10.1152/advan.00030.2017
3. Stott SRW. Mesolimbic Pathway [Internet]. Mesolimbic Pathway – an overview | ScienceDirect Topics. 2013. Available from: https://www.sciencedirect.com/topics/neuroscience/mesolimbic-pathway 4. Berk LS, Felten DL, Tan SA, Bittman BB, Westengard J. Modulation of neuroimmune parameters during the eustress of humor-associated mirthful laughter . Alternative therapies in health and medicine. U.S. National Library of Medicine; 2001. Available from: https://pubmed.ncbi.nlm.nih.gov/11253418/
5. Dfarhud D, Malmir M, Khanahmadi M. Happiness & Health: The Biological Factors Systematic Review Article. Iranian journal of public health. Tehran University of Medical Sciences; 2014. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4449495/
6. Van der wall CN, Kok RN. Laughter-inducing therapies: Systematic review and meta-analysis . Social Science & Medicine. Pergamon; 2019. Available from: https://www.sciencedirect.com/science/article/pii/S0277953619300851
7. Cho EA, Oh HE. Effects of laughter therapy on depression, quality of life, resilience and immune responses in breast cancer survivors. Journal of Korean Academy of Nursing. U.S. National Library of Medicine; 2011. Available from: https://pubmed.ncbi.nlm.nih.gov/21804337/